Setting `availableSize` for `RCTRootShadowView` on earlier stage

Summary:
Moving setting `availableSize` for `RCTRootShadowView` on earlier stage allows to prevent situations where `availableSize` is not specified yet, but Yoga layout is already happening.
Because `availableSize` equals {infinity, infinity} by default (in this case), Yoga returns a lot of nodes with infinit metrics, which confises UIKit.

Reviewed By: mmmulani

Differential Revision: D4672170

fbshipit-source-id: f9d8c84799dcbdb6b9230ddef6284d84df268833

React/Base/RCTRootContentView.h

@@ -22,6 +22,7 @@
 @property (nonatomic, readonly, strong) RCTTouchHandler *touchHandler;
 @property (nonatomic, assign) BOOL passThroughTouches;
 @property (nonatomic, assign) RCTRootViewSizeFlexibility sizeFlexibility;
+@property (nonatomic, readonly) CGSize availableSize;
 
 - (instancetype)initWithFrame:(CGRect)frame
                        bridge:(RCTBridge *)bridge

React/Base/RCTRootContentView.m

@@ -72,20 +72,22 @@ RCT_NOT_IMPLEMENTED(-(instancetype)initWithCoder:(nonnull NSCoder *)aDecoder)
   [self setNeedsLayout];
 }
 
+- (CGSize)availableSize
+{
+  CGSize size = self.bounds.size;
+  return CGSizeMake(
+      _sizeFlexibility & RCTRootViewSizeFlexibilityWidth ? INFINITY : size.width,
+      _sizeFlexibility & RCTRootViewSizeFlexibilityHeight ? INFINITY : size.height
+    );
+}
+
 - (void)updateAvailableSize
 {
   if (!self.reactTag || !_bridge.isValid) {
     return;
   }
 
-  CGSize size = self.bounds.size;
-  CGSize availableSize =
-    CGSizeMake(
-      _sizeFlexibility & RCTRootViewSizeFlexibilityWidth ? INFINITY : size.width,
-      _sizeFlexibility & RCTRootViewSizeFlexibilityHeight ? INFINITY : size.height
-    );
-
-  [_bridge.uiManager setAvailableSize:availableSize forRootView:self];
+  [_bridge.uiManager setAvailableSize:self.availableSize forRootView:self];
 }
 
 - (void)setBackgroundColor:(UIColor *)backgroundColor

React/Modules/RCTUIManager.m

@@ -27,6 +27,7 @@
 #import "RCTModuleData.h"
 #import "RCTModuleMethod.h"
 #import "RCTProfile.h"
+#import "RCTRootContentView.h"
 #import "RCTRootShadowView.h"
 #import "RCTRootViewInternal.h"
 #import "RCTScrollableProtocol.h"
@@ -381,7 +382,7 @@ dispatch_queue_t RCTGetUIManagerQueue(void)
   return RCTGetUIManagerQueue();
 }
 
-- (void)registerRootView:(UIView *)rootView
+- (void)registerRootView:(RCTRootContentView *)rootView
 {
   RCTAssertMainQueue();
 
@@ -393,6 +394,8 @@ dispatch_queue_t RCTGetUIManagerQueue(void)
   RCTAssert(existingView == nil || existingView == rootView,
             @"Expect all root views to have unique tag. Added %@ twice", reactTag);
 
+  CGSize availableSize = rootView.availableSize;
+
   // Register view
   _viewRegistry[reactTag] = rootView;
 
@@ -403,6 +406,7 @@ dispatch_queue_t RCTGetUIManagerQueue(void)
     }
 
     RCTRootShadowView *shadowView = [RCTRootShadowView new];
+    shadowView.availableSize = availableSize;
     shadowView.reactTag = reactTag;
     shadowView.backgroundColor = rootView.backgroundColor;
     shadowView.viewName = NSStringFromClass([rootView class]);

React/Views/RCTRootShadowView.m

@@ -13,10 +13,6 @@
 
 @implementation RCTRootShadowView
 
-/**
- * Init the RCTRootShadowView with RTL status.
- * Returns a RTL CSS layout if isRTL is true (Default is LTR CSS layout).
- */
 - (instancetype)init
 {
   self = [super init];